Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

Inmarsat PLC

Sedol B09LSH6

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

√

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

An event changing the breakdown of voting rights

Other (please specify):

3. Full name of person(s) subject to thenotification obligation: iii

¹Lansdowne Partners Limited being the General Partner of Lansdowne Partners Limited Partnership

²Lansdowne Partners International Limited

4. Full name of shareholder(s)  (if different from 3.):iv

SNC Nominees Ltd

Goldman Sachs Securities Nominees LtdVidacos Nominees Ltd

HSBC Client Holdings UK Ltd

(Registered Shareholders)

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

02/08/13

6. Date on which issuer notified:

06/08/13

7. Threshold(s) that is/are crossed orreached: vi, vii

12%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

Ordinary Shares

53,541,774

53,541,774

49,655,218

11.08%

GB00B09LSH68

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

CFD

N/A

N/A

N/A

3,599,792

Nominal

Delta

0.80%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

53,255,010

11.88%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable: xxi

Lansdowne Partners International Limited is the parent undertaking of Lansdowne Partners Limited.

Proxy Voting:

10. Name of the proxy holder:

Lansdowne Partners Limited

11. Number of voting rights proxy holder will ceaseto hold:

12. Date on which proxy holder will cease to holdvoting rights:

13. Additional information:

Based on ordinary shares in issue of 448,298,368.

14. Contact name:

Ruari Paton

15. Contact telephone number:

+44(0)20 7290 5500